The present invention relates generally to catheters, and more particularly to cardiac catheters having multiple lumens.
Implantable leads form an electrical connection between a pulse generator or other electronic device and a tissue or structure in the body. For example, leads transmit electric signals in one direction to stimulate cardiac tissue and in the opposite direction sensed from the cardiac tissue. To sense signals, leads typically include one or more electrical elements positioned on the lead. These electrical elements are typically referred to as electrodes and they are adapted to sense cardiac signals and to provide electrical energy to the cardiac tissue. Leads also typically include a lead connector pin at the lead""s proximal end. Lead connector pins are adapted to electrically and mechanically connect leads to the pulse generator or other electronic medical device. A flexible conductor electrically couples the electrode to the lead connector pin. Commonly, the flexible conductor takes the form of a single or multifilar wire coil. The flexible conductors are then surrounded by a layer of insulating material that together form what is referred to as the lead body. The lead body couples the lead connector pin at the proximal end with the electrodes at the distal end.
Cardiac pacemakers for treating bradycardia commonly employ pacing leads for connecting an electrical impulse generator to an excitable cardiac tissue, usually within the heart""s right ventricle. Researchers have found that cardiac stimulation can also be beneficial in treating patients suffering from congestive heart failure (CHF). By properly controlling the interval between the atrial contraction and the ventricular contraction (i.e., the AV interval) with the pacemaker, a heart may be induced to pump more efficiently. Pacing therapy for the treatment of CHF, however, often requires the ability to stimulate the left ventricle, either alone or in conjunction with right ventricle. One way of providing stimulation to the left ventricle is through the use of a left ventricular access (LVA) leads. This type of lead is introduced through the coronary sinus vein and advanced through the cardiac veins so as to position the one or more electrodes on the lead on the cardiac tissue adjacent the left ventricle.
The introduction of a lead into the cardiovascular system partially obstructs blood flow. This is especially true when the cardiac lead is implanted into the coronary veins, where placement of a lead into the coronary veins may exacerbate an individual""s cardiac condition. The size of the lead is also a concern when they are used in children. Children are inherently more susceptible to having blood flow obstructed because many of their blood vessels are simply too small to accommodate conventional implantable leads. As a result, these adult patients may not be suitable candidates for transvenous implanted leads because of the diameter of currently available leads.
Conventional lead bodies have an internal lumen that is coextensive with the lead body. The lumen is adapted to receive a stylet, where the stylet is used to push and steer the lead through the vessels to a target location within the heart. The lumen, however, constitutes a significant portion of the overall diameter of the lead body. Therefore, a trade-off of lead body diameter is made for the ability to utilize a stylet while implanting the cardiac lead. What is needed, however, is an apparatus, system and method which can allow for leads having lead bodies of reduced size to be implanted into the heart, including the cardiac veins.
The present subject matter provides an apparatus, system and method which addresses the need for handling and delivering cardiac leads having lead bodies of reduced size. In reducing the size of the cardiac lead, support and guidance structure is typically removed. The present subject matter provides the reduced size cardiac leads with support and guidance during the time that such support and guidance is needed, during implant. Once the leads have been implanted, the support and guidance structures that would typically have been left in the vasculature only to unnecessarily occlude the vasculature is removed. Thus, the present apparatus, system and method provide an important advancement in the delivery and placement of reduced size cardiac leads.
In one embodiment, there is provided a system having catheter and at least a first cardiac lead and a second cardiac lead. The catheter includes an elongate catheter body with at least two lumens, where each of the lumens is adapted to pass a cardiac lead. The elongate catheter body includes a first section and a second section. In one embodiment, the elongate catheter body has a tapered transition between the first section and the second section. A first lumen extends through the first section and the second section between a first inlet at the proximal end to a first outlet at the distal end. A second lumen extends through the first section between a second inlet at the proximal end to a second outlet in the first section. In one embodiment, the second outlet is located in the tapered region. The first cardiac lead is located at least partially in and passes through the first lumen of the elongate catheter body. The second cardiac lead is located in and at least partially in and passes through the second lumen of the elongate catheter body.
In positioning the leads in the heart, the catheter is first positioned at least partially within the heart. In one embodiment, a guidewire is first inserted into the heart. The catheter is positioned over the guidewire and then inserted into the heart. The guidewire is then removed from the heart and the cardiac leads are inserted into the lumens of the catheter. One the cardiac leads are implanted into the desired location within the heart, the elongate catheter is removed from the heart. In an alternative embodiment, the catheter is positioned at least partially within the heart without the use of a guidewire.
In order to allow the leads to pass more easily through the lumens, the walls of the lumens are coated with a lubricant. In an additional embodiment, the catheter body is made radiopaque to allow for the catheter to be visualized within the vasculature and heart. In an additional embodiment, the catheter body is splitable to allow the catheter to be more easily passed around the implanted leads and to removed the catheter from the patient. In one embodiment, the catheter body separate into two or more pieces to allow the catheter to passed around the leads. The splitable catheter body includes two or more segments, where the segments are defined by sections of the catheter body that are weaker relative to the remainder of the catheter body, where the two or more segments are adapted to separate from each other along the sections. In one embodiment, the sections along the catheter body are slits which extend longitudinally along the catheter body.
These and other embodiments, aspects, advantages, and features will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art by reference to the following description of the invention and referenced drawings or by practice of the invention. The aspects, advantages, and features of the invention are realized and attained by means of the instrumentalities, procedures, and combinations particularly pointed out in the appended claims.